Media processing device and control method for a media processing device

ABSTRACT

A media processing device does not execute a media transportation process if the height of media stacked in a media storage unit is at an over capacity level, and reliably prevents problems such as damage to the media transportation mechanism caused by collision with the stacked media. If in the media processing device the height of media stacked in a media storage unit  121, 122  is at a full stack level or over capacity level (step S 33  returns yes or step S 35  returns yes), an appropriate warning is output (step S 34  or step S 36 ) and collision accidents of the media transportation mechanism  131  can be prevented.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a media processing device that appliesspecific processes such as writing data to disc-shaped media such as CDsand DVDs and printing on the label side of the media, and to a controlmethod for the media processing device.

2. Related Art

Media processing systems for reading and writing data on disc media suchas CDs and DVDs, and printing on the label side of the media, generallyinclude a media processing device and a host computer.

The media processing device in this type of media processing system hasa media storage unit for storing the disc media, a media drive forwriting data to the media, a label printer for printing on the labelside of the media, and a media transportation mechanism for holding andcarrying the media to the media storage unit, the media transferposition of the media tray disposed to the media drive, and the mediatransfer position of the label printer. The host computer controlsoperation of the media drive, the label printer, and the mediatransportation mechanism in the media processing device.

In order to enable continuous processing of a large number of media, themedia storage unit of the media processing device may include both asupply stacker and a discharge stacker. The supply stacker storesnumerous blank media stacked vertically. The discharge stacker similarlystores numerous processed media in a vertical stack after the datawriting process or label printing process is completed. See, forexample, Japanese Unexamined Patent Appl. Pub. JP-A-2000-260172 andJapanese Unexamined Patent Appl. Pub. JP-A-2002-056584.

The media processing device may execute various media transportationprocesses, including, for example, carrying the blank media stored inthe supply stacker to the media transfer position of the internal mediadrive, and then carrying the processed media after the data writingprocess is completed in the media drive from the media transfer positionof the media drive to the discharge stacker. The media may alternativelybe carried after the data writing process to the media transfer positionof the internal label printer, and the processed media is then carriedafter the label is printed by the label printer from the media transferposition of the label printer to the discharge stacker.

As this media processing device continues operating and media arecarried to the discharge stacker, the actual height of the media stackin the discharge stacker may exceed the maximum stackable height of thedischarge stacker.

Japanese Unexamined Patent Appl. Pub. JP-A-H06-247617 teaches a fullstacker detection device that detects if the number of printed sheetsstored in the discharge stacker of a printer exceeds a certain level.

If the media transportation mechanism continues carrying media to thedischarge stacker after the discharge stacker has become full, thetransportation arm of the media transportation mechanism may collidewith media stacked in the discharge stacker, possibly resulting indamage to the media transportation mechanism, damage to the stackedmedia, or damage to the media being carried to the discharge stacker,for example.

SUMMARY

With the media processing device and control method therefor accordingto the present invention, the media transportation mechanism does notconvey media to the media storage unit when the height of the mediastack in the media storage unit exceeds the maximum height of the stackat which media can be stacked by the transportation operation of themedia transportation mechanism.

A media processing device according to a first aspect of the inventionhas a media storage unit that stores media; a media drive that writesdata to the media; a media transportation mechanism that picks up media,carries the media to the media storage unit and a drive tray of themedia drive, and releases the media at the destination; a media detectorthat detects the stack height of media stacked in the media storageunit; and a controller that determines if the media stack heightdetected by the media detector exceeds a maximum stack height for themedia storage unit, and if the media stack height exceeds the maximumstack height outputs a warning that the maximum stack height isexceeded.

A media processing device according to another aspect of the inventionhas a media storage unit that stores media; a media transportationmechanism that picks up media, carries the media, and releases the mediaat the destination; a media detector that detects the stack height ofmedia stacked in the media storage unit; and a controller thatdetermines if the media stack height detected by the media detectorexceeds a first value for the media storage unit, and if the media stackheight exceeds the first value outputs a warning that the first value isexceeded.

Another aspect of the invention is a control method having a mediastorage unit that stores media, a media transportation mechanism thatpicks up media, carries the media, and releases the media at thedestination, and a media detection unit that detects the stack height ofmedia stacked in the media storage unit, the control method including: adetection step of detecting the media stack height; a first evaluationstep of determining if the detected media stack height exceeds a firstvalue for the media storage unit; and a warning step of outputting awarning that the first value is exceeded if the media stack heightexceeds the first value.

The invention thus monitors the media stack height in the media storageunit and outputs a warning if the media stack height approaches acondition exceeding the maximum stack height. The operator of the mediaprocessing device can thus take action appropriate to the warning. Morespecifically, before the media transportation mechanism operates theoperator can take action to remove media stacked above the maximum stackheight from the media storage unit. Damage to the media transportationmechanism and damage to the media resulting from collision between themedia transportation mechanism and media stacked above the maximum stackheight can thus be prevented.

Preferably, the controller of the media processing device determines ifthe media stack height detected by the media detector exceeds a fullstack level that is set lower than the maximum stack height, and if themedia stack height exceeds the full stack level the controlled outputs awarning that the full stack level is exceeded.

This aspect of the invention outputs a warning that the full stack levelis exceeded if the media stack height exceeds the full stack level. Thefull stack level is below the maximum stack height and is a height atwhich the media picking process is possible but the media releaseprocess is not possible. The operator can therefore be warned during theinitialization process and the operator can quickly remove media beforemedia is stacked to the maximum stack height during normal mediaprocessing. Damage to the media transportation mechanism and damage tothe media resulting from collision between the media transportationmechanism and media stacked above the maximum stack height can thus beprevented during normal media processing.

In a media processing device according to another aspect of theinvention the controller determines if the media stack height exceedsthe maximum stack height when the media transportation mechanismexecutes the media picking process, detects the media stack height inthe media storage unit from which media was picked after picking upmedia, and updates and stores the media stack height in the storageunit.

In a media processing device according to another aspect of theinvention the controller determines if the media stack height exceedsthe maximum stack height and determines if the media stack heightexceeds the full stack level when the media transportation mechanismexecutes the media release process, detects the media stack height inthe media storage unit in which media was released after releasing themedia, and updates and stores the media stack height in the storageunit.

This aspect of the invention enables determining only if the maximumstack height is exceeded when picking up media, and therefore enablesquickly executing the media picking process. When releasing the media,however, whether the full stack level is exceeded can be determined inaddition to determining if the maximum stack height is exceeded, and themedia releasing process can therefore be restricted when the media stackheight exceeds the full stack level. It is therefore possible to preventstacking media to the maximum stack height when proceeding to normalmedia processing and the media release process after the initializationprocess.

In the media processing device according to another aspect of theinvention the media detector detects the distance descended by the mediatransportation mechanism from a predetermined height until the media onthe top of the stack in the media storage unit is detected, andcalculates the height of media stacked in the media storage unit bysubtracting the distance descended from the predetermined height of themedia transportation mechanism before descending.

Other objects and attainments together with a fuller understanding ofthe invention will become apparent and appreciated by referring to thefollowing description and claims taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of a preferred embodiment of a mediaprocessing system incorporating a media processing device according tothe present invention.

FIG. 2 is an oblique view showing the internal structure of the mediaprocessing device shown in FIG. 1.

FIG. 3 describes the movement of the media transportation mechanism inthe media processing device shown in FIG. 2.

FIG. 4 is an enlarged oblique view of the media transportation mechanismshown in FIG. 2.

FIG. 5 describes the media stacking conditions in the media storage unitshown in FIG. 1.

FIG. 6 is a flowchart describing the initialization process that isexecuted by the media processing device shown in FIG. 1 when the powerturns on or the cover is closed.

FIG. 7 is a flow chart describing the media picking process that isexecuted when the host computer sends a media picking command to themedia processing device shown in FIG. 1.

FIG. 8 is a flow chart describing the release process that is executedwhen the host computer sends a media release command to the mediaprocessing device shown in FIG. 1.

DESCRIPTION OF EMBODIMENTS

A preferred embodiment of a media processing device according to thepresent invention is described below with reference to the accompanyingfigures.

FIG. 1 is a schematic block diagram of a preferred embodiment of a mediaprocessing system incorporating a media processing device according tothe present invention. FIG. 2 is an oblique view showing the internalstructure of the media processing device shown in FIG. 1. FIG. 3describes the movement of the transportation arm of the mediatransportation mechanism in the media processing device shown in FIG. 2.FIG. 4 is an enlarged oblique view of the media transportation mechanismshown in FIG. 2. FIG. 5 describes the media stacking conditions in themedia storage unit shown in FIG. 1. FIG. 6 is a flow chart describingthe initialization process that is executed by the media processingdevice shown in FIG. 1 when the power turns on or the cover is closed.FIG. 7 is a flow chart describing the media picking process that isexecuted when the host computer sends a media picking command. FIG. 8 isa flow chart describing the release process that is executed when thehost computer sends a media release command.

The media processing system shown in FIG. 1 includes a media processingdevice 200 and a host computer 100. The media processing device 200reads and writes data on disc-shaped media such as CDs and DVDS, andprints on the label side of the media. The invention is not limited tothis configuration, however, and can be applied to any processing devicethat has a media storage unit, a mechanism for transporting media, and aconfiguration for detecting the media.

As shown in FIG. 2 and FIG. 3, the media processing device 200 has firstto fourth media storage units 121, 122, 171, and 172 for storingdisc-shaped media such as CDs and DVDs, two media drives 141 for writingdata to the media, a printer 111 for printing on the label side of themedia, and a media transportation mechanism 131. The mediatransportation mechanism 131 holds and carries the media between themedia storage units 121, 122, 171, and 172, the media transfer positionA of the drive trays 141 a of the media drives 141, and the mediatransfer position of the printer 111.

Operation of the media drives 141, the printer 111, and the mediatransportation mechanism 131 of the media processing device 200 can becontrolled by the host computer 100.

FIG. 2 shows the arrangement of the devices inside the media processingdevice 200 with the outside walls rendered by a box-like case 102 notshown. Access covers not shown that can open to the right and left sidesare also disposed to the front of the case 102. An operating panel 105populated with indicators and operating buttons is disposed to the topright part of the case 102 as shown in FIG. 3.

When the access covers not shown disposed to the front of the case 102are opened, the media storage units 121, 122, 171, and 172, printer 111,and other components shown in FIG. 2 are exposed, enabling the operatorto load and remove media from the media storage units 121, 122, 171, and172 and replace the ink cartridge of the printer 111.

The basic application of each of the first to fourth media storage units121, 122, 171, and 172 is preset.

The first media storage unit 121 shown at the top right in FIG. 2 isbasically used as a supply stacker for storing a plurality of (such as50) blank media (unused media to which data has not been written) in avertical stack, but can also be used to store processed media after thedata writing process or the label printing process.

The second media storage unit 122 located directly below the first mediastorage unit 121, and the fourth media storage unit 172 located on theleft side of the second media storage unit 122, are basically used asdischarge stackers for storing a plurality of (such as 50) processedmedia (the media after the data writing process or the label printingprocess is completed) in a vertical stack, but can also be used to storeblank media.

The fourth media storage unit 172 holds a removable third media storageunit 171, which is shaped like a bucket with a handle. The third mediastorage unit 171 is used to store a smaller number of media in a recessformed in a drawer 170 that can slide in and out at the front of themedia processing device 200.

As shown in FIG. 3 and FIG. 4, the media transportation mechanism 131has a vertical guide shaft 135 disposed vertically inside the case 102,and a transportation arm 136 supported so that it can move up and downand pivot on the vertical guide shaft 135. Fingers 151 for holding thecenter hole of the media are disposed in the middle at the distal end ofthe transportation arm 136.

A part of the transportation arm 136 is connected to a timing belt 153,which is driven in a loop behind the vertical guide shaft 135 by meansof an elevator motor 152, so that as the timing belt 153 moves thetransportation arm 136 travels up or down on the vertical guide shaft135.

The transportation arm 136 is rendered in unison with a horizontalsupport plate 154 attached pivotably to the bottom end of the verticalguide shaft 135, and can swing around the vertical guide shaft 135 whena fan-shaped gear not shown affixed to the top of the horizontal supportplate 154 is driven rotationally around the vertical guide shaft 135 bythe pivot motor 155.

A media detector 156 for detecting if media is present, and a light 158that outputs illumination 158a downward, are disposed near the fingers151 of the transportation arm 136.

The media detector 156 is disposed so that it can descend and retractfrom the bottom of the transportation arm 136, and detects that media ispresent when the transportation arm 136 descends to the top of the mediain the media storage unit, for example, and the media detector 156contacts the media and is pushed inside the transportation arm 136.

The detection result from the media detector 156 is used to get thestart timing of the media picking operation of the fingers 151, and todetect the stack height of media in the media storage units 121, 122,171, and 172.

Using different combinations of the pivoting actions indicated by arrowsA to H in FIG. 3 and the elevator actions indicated by arrows I and J,the transportation arm 136 moves the position of the fingers to thepoints indicated by numbers [1] to [6] in the figure, and carries mediabetween the media storage units 121, 122, 171, and 172, the drive trays141 a of the media drives 141, and the media transfer position of theprinter 111.

More specifically, the points [1] to [6] in FIG. 3 are: [1] the homeposition (standby position) of the transportation arm 136; [2] theposition of the first media storage unit 121; [3] a desired positionbetween the home position and the first media storage unit 121; [4] amidpoint; [5] the position of the second media storage unit 122; and [6]a desired position between the midpoint and the second media storageunit 122.

As shown in FIG. 3, the media processing device 200 has a mediatransportation mechanism control unit 190 that controls driving themedia transportation mechanism 131. This media transportation mechanismcontrol unit 190 can communicate with the host computer 100. The mediatransportation mechanism control unit 190 has firmware for controllingmoving the transportation arm 136 in response to transportation arm 136movement commands sent from the host computer 100, and thus transportsthe media according to the transportation arm 136 movement command sentfrom the host computer 100.

As the media processing device 200 continues carrying media between themedia storage units 121, 122, 171, and 172, one or more of the mediastorage units could become filled beyond the maximum stack height H(first value) to which media can be stacked in the media storage unit bythe media transportation mechanism 131. The two reference heights setfor each media storage unit are described next with reference to FIG. 5.

FIG. 5 shows the media stack that grows in the second media storage unit122.

This embodiment of the invention sets two reference heights for thesecond media storage unit 122. The maximum stack height H is set to avalue at which the transportation arm 136 can be expected to collidewith the stacked media if the media is stacked to a height exceedingthis value. In other words, the maximum stack height H is the maximumheight at which the transportation arm 136 can pivot normally withouttouching the stacked media during the transportation process.

The full stack level h (second value) is the height at which thetransportation arm 136 can pick up media but cannot release media, andis set lower than the maximum stack height H.

In this embodiment of the invention the range from the bottom of themedia storage unit to the full stack level h is normal range B, and therange from the maximum stack height H to the full stack level h is thefull stack range C. If the disc M at the top of the stack is within thefull stack range C, the stack is said to be full (a full stack), and ifthe disc M at the top of the stack is above the maximum stack height H,the stack is said to be over capacity. If the transportation arm 136tries to pass over the second media storage unit 122 when the stack isover capacity, the transportation arm 136 will collide with the top discM in the stack.

Therefore, if an over capacity condition occurs, the media processingdevice 200 according to this embodiment of the invention enablescontrolling operation so that the transportation arm 136 of the mediatransportation mechanism 131 does not pass over the second media storageunit 122 and collide with the media. More specifically, the mediaprocessing device 200 monitors the media stack height in each of themedia storage units 121, 122, 171, and 172, and issues a warning orlimits operation of the media transportation mechanism 131 according tothe stack height.

More specifically, when the media processing device 200 power turns onor an access cover not shown for loading and removing media from themedia storage units 121, 122, 171, and 172 is closed, the initializationprocess shown in FIG. 6 is executed.

The process shown in FIG. 6 is the initialization process that isexecuted when the media processing device 200 power turns on or anaccess cover not shown for loading and removing media from the mediastorage units 121, 122, 171, and 172 is closed. It is assumed below thatthe fourth media storage unit 172 is set in the third media storage unit171.

When the power turns on or the cover is closed, the operator may haveloaded or removed media from the media storage units 121, 122, 171, and172 and the height of the media stack may have changed. The media stackheight in each of the media storage units 121, 122, 171, and 172 istherefore detected again.

When it is detected that the media processing device 200 power turned onor the cover closed, the initialization process starts and thetransportation arm 136 of the media transportation mechanism 131 detectsthe height of the media stack in each of the stackers 121, 122, 172(step S11). The detected media height is then stored in a predeterminedrecording means (storage means) in the media transportation mechanismcontrol unit 190 (step S12).

The media height in each media storage unit is detected as follows.

The transportation arm 136 moves to a position above the media storageunit in which the media height is to be measured, and the transportationarm 136 then descends. To detect the media height in the first mediastorage unit 121, the transportation arm 136 moves to position [2] abovethe stacker 121 shown in FIG. 3 and then descends. The number of stepsthe elevator motor 152 moves until the media detector 156 detects thetop disc is counted. The distance of the descent corresponding to thenumber of counted steps is then subtracted from the height of thetransportation arm 136 at a predetermined position before descent startsto calculate the stack height of the media in the media storage unit.

Whether the media stack height saved in step S12 exceeds the maximumstack height H shown in FIG. 5 is then determined (step S13). If themedia stack height exceeds the maximum stack height H (step S13 returnsYes), an over capacity warning is output by causing an indicator on theoperating panel 105 to light, for example. The media storage unit wherethe over capacity state was detected is also reported to the hostcomputer 100 (step S14).

If in step S13 the media stack height does not exceed the maximum stackheight H (step S13 returns No), whether the media stack height saved instep S12 exceeds the full stack level h is determined (step S15). If themedia stack height exceeds the full stack level h (step S15 returnsYes), a full stack warning is output by causing an indicator on theoperating panel 105 to light, for example. The media storage unit wherethe full stack was detected is also reported to the host computer 100(step S16).

If in step S15 the full stack level h is not exceeded (step S15 returnsNo), neither the over capacity or the full stack conditions apply. Morespecifically, the media stacked in the media storage unit are within thenormal range B, and the transportation arm 136 is confirmed to be ableto operate normally.

This same process is applied to each other media storage units, and theinitialization process then ends.

The normal media transportation process that executes after theinitialization process is described next with reference to FIG. 7 andFIG. 8. The media picking process is described first with reference toFIG. 7. The process shown in FIG. 7 is executed when a media pickcommand is received from the host computer 100 after the initializationprocess.

When a media pick command is received from the host computer 100 (stepS21 returns Yes), the media height of the specified media storage unitis read from the media height values of the media storage units saved inthe recording means in step S12 in FIG. 6 (step S22).

Whether the read media height exceeds the maximum stack height H shownin FIG. 5 is then determined (step S23). If the media stack heightexceeds the maximum stack height H (step S23 returns Yes), an overcapacity warning is output by causing an indicator on the operatingpanel 105 to light, for example. The media storage unit where the overcapacity state was detected is also reported to the host computer 100(step S24).

If in step S23 the media stack height does not exceed the maximum stackheight H (step S23 returns No), the transportation arm 136 moves to theposition of the specified media storage unit, descends, and picks up thesingle media M on the top of the stack (step S25). After the media M ispicked up, the height of the remaining stack is detected (step S26).Media height detection in this case does not use the transportation arm136, and subtracts the height equal to the thickness of one disc issubtracted from the media stack height read in step S22. The detectedmedia stack height is updated and saved (step S27), and the mediapicking process ends.

The media release process is described next with reference to FIG. 8.The process shown in FIG. 8 executes when a media release command isreceived from the host computer 100 after the initialization process.

When a media release command is received from the host computer 100(step S31 returns Yes), the media height of the specified media storageunit is read from the media height values of the media storage unitssaved in the recording means (step S32).

Whether the read media height exceeds the maximum stack height H shownin FIG. 5 is then determined (step S33). If the media stack heightexceeds the maximum stack height H (step S33 returns Yes), an overcapacity warning is output by causing an indicator on the operatingpanel 105 to light, for example. The media storage unit where the overcapacity state was detected is also reported to the host computer 100(step S34).

If in step S33 the media stack height does not exceed the maximum stackheight H (step S33 returns No), whether the read media stack heightexceeds the full stack level h is determined (step S35). If the mediastack height exceeds the full stack level h (step S35 returns Yes), afull stack warning is output by causing an indicator on the operatingpanel 105 to light, for example. The media storage unit where the fullstack was detected is also reported to the host computer (step S36).

If in step S35 the full stack level h is not exceeded (step S35 returnsNo), neither the over capacity or the full stack conditions apply. Morespecifically, the media stacked in the media storage unit specified forreleasing the disc are within the normal range B, and the transportationarm 136 is confirmed to be able to operate normally. The transportationarm 136 therefore moves to the position of the media storage unit wherethe media is to be released, descends, and releases the held singlemedia M held by the transportation arm 136 onto the top of the stack(step S37). After the media M is released, the height of the stack isdetected (step S38). Media height detection in this case uses thetransportation arm 136, and detects the stack height in the same way asin the initialization process described in step S11 in FIG. 6. Thedetected media stack height is updated and saved (step S39), and themedia release process ends.

This embodiment of the invention monitors the stack height of media ineach media storage unit during operation of the media processing device200, and outputs a warning if any media storage unit is detected to bein an over capacity state or full stack state. If a command forreleasing media into a media storage unit that is in a full stack stateis received from the host computer, the media processing device 200 doesnot execute the release command.

As thus described, if during operation of the media processing device200 the media height in any of the media storage units approaches anover capacity state exceeding the maximum height to which media can bestacked by the media transportation mechanism 131, the media processingdevice 200 issues a warning without executing the pickup command orrelease command received from the host computer 100. Damage to the mediatransportation mechanism, damage to the media, and other problems causedby the transportation arm 136 colliding with media stacked in a mediastorage unit can thus be reliably prevented.

Furthermore, because an appropriate warning is issued to the operator ifa full stack or over capacity condition occurs, the operator can quicklyact to correct the stack full or over capacity condition.

In addition, the media processing device 200 according to thisembodiment of the invention executes the initialization process shown inFIG. 6 whenever the power turns on or the cover closes to remeasure thestack height of media in each media storage unit. As a result, if theoperator adds or removes media to a media storage unit so that the mediastack height in the media storage unit changes from the previous height,the new media stack height in the media storage unit can be accuratelydetermined.

Furthermore, each time the media transportation mechanism executes amedia transportation process (picking process or releasing process)after the initialization process, the media stack height stored in therecording means can be updated. By thus constantly monitoring the mediastack height in each media storage unit, collision of the mediatransportation mechanism 131 with the media can be reliably prevented.

The invention being thus described, it will be obvious that it may bevaried in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

1. A media processing device comprising: a media storage unit that stores media; a media drive that writes data to the media; a media transportation mechanism that picks up media, carries the media to the media storage unit and a drive tray of the media drive, and releases the media at the destination; a media detector that detects the stack height of media stacked in the media storage unit; and a controller that determines if the media stack height detected by the media detector exceeds a maximum stack height for the media storage unit, and if the media stack height exceeds the maximum stack height outputs a warning that the maximum stack height is exceeded.
 2. The media processing device described in claim 1, further comprising: a storage unit that stores the detected media stack height.
 3. The media processing device described in claim 1, wherein: the controller determines if the media stack height detected by the media detector exceeds a full stack level that is set lower than the maximum stack height.
 4. The media processing device described in claim 3, wherein: the controller outputs a warning if the media stack height exceeds the full stack level.
 5. The media processing device described in claim 1, wherein: the controller determines if the media stack height exceeds the maximum stack height when the media transportation mechanism executes the media picking process.
 6. The media processing device described in claim 5, wherein: the controller detects the media stack height in the media storage unit from which media was picked after picking up media, and updates and stores the media stack height in the storage unit.
 7. The media processing device described in claim 3, wherein: the controller determines if the media stack height exceeds the maximum stack height and determines if the media stack height exceeds the full stack level when the media transportation mechanism executes the media release process.
 8. The media processing device described in claim 7, wherein: the controller detects the media stack height in the media storage unit in which media was released after releasing the media, and updates and stores the media stack height in the storage unit.
 9. The media processing device described in claim 1, wherein: the media detector detects the distance descended by the media transportation mechanism from a predetermined height until the media on the top of the stack in the media storage unit is detected.
 10. The media processing device described in claim 9, wherein: the media detector calculates the height of media stacked in the media storage unit by subtracting the distance descended from the predetermined height of the media transportation mechanism before descending.
 11. A media processing device comprising: a media storage unit that stores media; a media transportation mechanism that picks up media, carries the media, and releases the media at the destination; a media detector that detects the stack height of media stacked in the media storage unit; and a controller that determines if the media stack height detected by the media detector exceeds a first value for the media storage unit, and if the media stack height exceeds the first value outputs a warning that the first value is exceeded.
 12. The media processing device described in claim 11, further comprising: a storage unit that stores the detected media stack height.
 13. The media processing device described in claim 11, wherein: the controller determines if the media stack height detected by the media detector exceeds a second value that is set lower than the first value, and if the second value is exceeded outputs a warning that the second value is exceeded.
 14. The media processing device described in claim 11, wherein: the controller determines if the media stack height exceeds the first value when the media transportation mechanism executes the media picking process.
 15. The media processing device described in claim 14, wherein: the controller detects the media stack height in the media storage unit from which media was picked after picking up media, and updates and stores the media stack height in the storage unit.
 16. The media processing device described in claim 3, wherein: the controller determines if the media stack height exceeds the first value and determines if the media stack height exceeds the second value when the media transportation mechanism executes the media release process.
 17. The media processing device described in claim 16, wherein: the controller detects the media stack height in the media storage unit in which media was released after releasing the media, and updates and stores the media stack height in the storage unit.
 18. The media processing device described in claim 11, wherein: the media detector detects the distance descended by the media transportation mechanism from a predetermined height until the media on the top of the stack in the media storage unit is detected.
 19. The media processing device described in claim 18, wherein: the media detector calculates the height of media stacked in the media storage unit by subtracting the distance descended from the predetermined height of the media transportation mechanism before descending.
 20. A control method for a media processing device having a media storage unit that stores media, a media transportation mechanism that picks up media, carries the media, and releases the media at the destination, and a media detection unit that detects the stack height of media stacked in the media storage unit, the control method comprising: a detection step of detecting the media stack height; a first evaluation step of determining if the detected media stack height exceeds a first value for the media storage unit; and a warning step of outputting a warning that the first value is exceeded if the media stack height exceeds the first value. 